Stop Light Control Relay Malfunction - Electronically Controlled Brake System

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1380/64: Stop Light Control Relay Malfunction
C1380/64 - Stop Light Control Relay Malfunction

DESCRIPTION

Upon receiving the hill-start assist control operating signal from the skid control ECU, the relay contact turns on and the stop light comes on.





WIRING DIAGRAM

Refer to DTC C1249/49 C1249.

INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU, perform initialization and calibration of the linear solenoid valve Initialization.

HINT
When C1249/49 is output together with C1380/64, inspect and repair the trouble areas indicated by C1249/49 first C1249.

PROCEDURE

1. CHECK STOP LIGHT OPERATION

(a) Check that the stop lights come on when the brake pedal is depressed and go off when the brake pedal is released.

OK:





NG -- GO TO LIGHTING SYSTEM (PROBLEM SYMPTOMS TABLE) Symptom Related Diagnostic Procedures
OK -- Continue to next step.

2. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





(d) Check that the stop light switch condition observed on the Techstream changes according to brake pedal operation.

OK:

The Techstream displays ON and OFF according to brake pedal operation.

NG -- INSPECT SKID CONTROL ECU (STP TERMINAL)
OK -- Continue to next step.

3. PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT CONTROL RELAY)

(a) Select the Active Test on the Techstream Data List / Active Test.

ABS/VSC/TRAC





(b) Perform the Active Test of the stop light control relay using the Techstream.

(c) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





(d) Check for stop light control relay operation using the Data List and stop light operation while performing an Active Test.

Result:





B -- INSPECT ECU IG NO. 2 FUSE
A -- Continue to next step.

4. INSPECT SKID CONTROL ECU (STP2 TERMINAL)

(a) Turn the ignition switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

(c) Disconnect the A44 skid control ECU connector.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STP2 CIRCUIT)
OK -- Continue to next step.

5. RECONFIRM DTC

(a) Reconnect the skid control ECU connector.

(b) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the ignition switch to ON (READY).

(d) Perform a road test.

(e) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result:





B -- REPLACE SKID CONTROL ECU Removal

A -- CHECK FOR INTERMITTENT PROBLEMS How To Proceed With Troubleshooting

6. INSPECT ECU IG NO. 2 FUSE

(a) Remove the ECU IG NO. 2 fuse from the main body ECU (instrument panel junction block).





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





NG -- REPLACE FUSE
OK -- Continue to next step.

7. INSPECT STOP LIGHT CONTROL RELAY (STOP)

(a) Turn the ignition switch off.





(b) Remove the stop light control relay from the engine room relay block.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





NG -- REPLACE STOP LIGHT CONTROL RELAY (STOP)
OK -- Continue to next step.

8. INSPECT ENGINE ROOM RELAY BLOCK (POWER SOURCE TERMINAL)





(a) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

9. INSPECT SKID CONTROL ECU (STP0)

(a) Install the stop light control relay.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.





(c) Disconnect the A45 skid control ECU connector.

(d) Turn the ignition switch to ON.

(e) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE SKID CONTROL ECU Removal

10. INSPECT SKID CONTROL ECU (STP TERMINAL)

(a) Turn the ignition switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(c) Disconnect the A47 skid control ECU connector.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STP1 CIRCUIT)

OK -- REPLACE SKID CONTROL ECU Removal